esp32 -ESP-idf 读取sht40温湿度-优快云博客

本文链接：https://blog.youkuaiyun.com/JINGACEA/article/details/131681790

该程序使用ESP32通过I2C总线扫描连接的设备，并对SHT40传感器进行高精度的温湿度测量。首先，它遍历I2C地址空间寻找设备，然后向SHT40发送测量命令并读取6字节数据，解析这些数据以获取温度和湿度值。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

idf 4.4.4 版本

程序内容：

1先对所有地址扫描打印出连接设备的地址

2在给i2c发送0xFD（为sht40：以高精度（高重复性）测量T&RH[2*8位T数据的指令）读取6位数据然后解析。

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_err.h"
#include "esp_log.h"
#include "driver/i2c.h"

#define I2C_MASTER_SCL_IO 22      // I2C专用时钟线GPIO
#define I2C_MASTER_SDA_IO 21      // I2C专用数据线GPIO
#define I2C_MASTER_NUM I2C_NUM_0  // I2C总线号
#define I2C_MASTER_FREQ_HZ 100000 // I2C总线频率

static const char *TAG = "I2C scanner";

void i2c_scanner_task(void *arg)
{
    i2c_config_t conf;
    conf.mode = I2C_MODE_MASTER;
    conf.sda_io_num = I2C_MASTER_SDA_IO;
    conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
    conf.scl_io_num = I2C_MASTER_SCL_IO;
    conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
    conf.master.clk_speed = I2C_MASTER_FREQ_HZ;
    i2c_param_config(I2C_MASTER_NUM, &conf);
    i2c_driver_install(I2C_MASTER_NUM, I2C_MODE_MASTER, 0, 0, 0);

    printf("Scanning I2C bus...\n");

    for (int address = 0x03; address <= 0x77; address++)
    {
        i2c_cmd_handle_t cmd = i2c_cmd_link_create();
        i2c_master_start(cmd);
        i2c_master_write_byte(cmd, (address << 1) | I2C_MASTER_WRITE, true);
        i2c_master_stop(cmd);

        esp_err_t ret = i2c_master_cmd_begin(I2C_MASTER_NUM, cmd, 100);
        if (ret == ESP_OK)
        {
            printf("Device found at address 0x%02X\n", address);
        }

        i2c_cmd_link_delete(cmd);

        vTaskDelay(10);
    }

    ESP_LOGI(TAG, "I2C Master Initialized");

    uint8_t c=0xFD;
    while (1)
    {
        i2c_cmd_handle_t cmd = i2c_cmd_link_create();
        i2c_master_start(cmd);
        i2c_master_write_byte(cmd, (0x44 << 1) | I2C_MASTER_WRITE, true);
        i2c_master_write(cmd, &c,1, true);
        i2c_master_stop(cmd);
        esp_err_t ret = i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000 / portTICK_PERIOD_MS);
        i2c_cmd_link_delete(cmd);

        if (ret != ESP_OK)
        {
            ESP_LOGE(TAG, "%dI2C write failed", ret);
        }
        vTaskDelay(50);
        uint8_t a[6] = {0, 0, 0, 0, 0, 0};
        cmd = i2c_cmd_link_create();
        i2c_master_start(cmd);
        i2c_master_write_byte(cmd, (0x44 << 1) | I2C_MASTER_READ, true);
        for (int i = 0; i < 6; i++)
        {
            i2c_master_read_byte(cmd, &a[i], I2C_MASTER_ACK);
        }
        i2c_master_stop(cmd);
        ret = i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000);
        i2c_cmd_link_delete(cmd);
        if (ret == ESP_OK)
        {
            for (int i = 0; i < 6; i++)
            {
                printf(" %d ", a[i]);
            }
            printf("\n");
            float t_ticks = (uint16_t)a[0] * 256 + (uint16_t)a[1];
            float rh_ticks = (uint16_t)a[3] * 256 + (uint16_t)a[4];
            float temperature = -45 + 175.0 * t_ticks / 65535.0;
            float humidity = -6 + 125.0 * rh_ticks / 65535.0;
            printf("温度：%.2lf \n", temperature);
            printf("湿度：%.2lf \n", humidity);
        }

        vTaskDelay(1000);
    }
    i2c_driver_delete(I2C_MASTER_NUM);
    vTaskDelete(NULL);
}

void app_main()
{
    xTaskCreate(i2c_scanner_task, "i2c_scanner_task", 2048, NULL, 10, NULL);
}